Central & Peripheral Nervous System

DIVISION OF THE CENTRAL NERVOUS SYSTEM : Brain Spinal cord

Cerebrum, Cerebellum, Brain Stem, and Spinal Cord

Division of the Peripheral Nervous system Afferent: stimuli both internal and external Internal: Stretch Receptors External: Integumentary receptors Messiner corpusle: touch Pacinian corpusle: pressure Nociceptor: pain Thermoreceptor: heat Sensory Nerves: Afferent Motor Nerves: Efferent Efferent: Response to effectors Two functional divisions Somatic: Skeletal muscle Autonomic: Cardiac & Smooth muscles Glands

Integumentary Sensory: Afferent

Autonomic Nervous System Efferent Cardiac Muscle, Smooth Muscle, and Glands Sympathetic Homeostasis: Calming Self-Maintenance Activities Balance the Sympathetic response Decrease HR, RR, BP Increase blood flow Digestive system Adrenals stop releasing Adrenaline Release of glycogen Stimulates liver to store BS Parasympathetic : Fight or Flight Increase HR, RR, BP, BS Decrease blood flow digestive Adrenaline (Stress Hormone) released for the Adrenal glands Pupils Dilate Increase Blood Flow to Muscles Senses Heighten Release of glucagon stimulates liver to release glucose increase BS

Autonomic Nervous system Fight or Flight: Sympathetic Homeostasis: Parasympathetic

Structures CNS Cerebrum Cerebellum Meningies Ventricles Medulla Oblongata Corpus Callosum Pons Midbrain Spinal cord

Cerebrum Largest part of the brain Divided into hemispheres Each hemisphere has four lobes (F,T,P,O) Connected by the CORPUS CALLOSUM

Corpus Callosum Thick band of nerve fibres connect the brain cells in one hemisphere to those in the other hemisphere allows for constant communication Aids motor coordination of left and right side Example : You read a geometry problem in a textbook. The words are seen and the visual forms translated into meaning by the language center in the left hemisphere. To solve the problem you have to imagine a cone shaped object. This is accomplished by centers in the right hemisphere. The solution is written down using language generated by the left hemisphere. What would happen in cases like this if the callosum was damaged ?

Left and Right Side of the Brain Left : Logical words logic numbers analysis lists linearity and sequence Right: Creative creative brain rhythm spatial awareness colour imagination daydreaming holistic awareness and dimension

Left: Logical Right: Creative

Lobes for the Brain

Frontal Lobes: anterior aspect of cerebrum planning organizing problem solving personality reasoning Intuition or perception behavior and emotions

Occipital Lobes: located posterior cerebrum and superior to cerebellum visual processing color recognition vision recognition Occipital Lobe

Parietal Lobes: located superior to temporal lobes of the cerebrum cognition (acquiring knowledge by the use of reasoning, intuition, or perception) information processing pain and touch sensation spatial orientation speech and visual perception. Parietal Lobe

Temporal Lobe: Medial to ears, superior to Occipital lobes emotional responses hearing speech. differentiate smells and sounds Memory (Hippocampus & Amygdala) information sorting short and long term memory. right lobe visual memory left verbal memory Temporal lobe Hippocampus

Sensory Cortex: Sensory Imput Motor Cortex: Motor Response

Meninges: membranes that protect Brain & Spinal Cord 3 Layers Dura Mater-toughest and outermost layer Arachnoid Mater (resembles a spider web) middle layer Pia Mater-inner layer and most delicate sits directly on top of the brain and spinal cord Space between Arachnoid and Pia Mater has cerebrospinal fluid (CSF)

Layers of the Meninges What is inflammation of the Meningies called? Why is it serious? What covers the Brain and the Spinal Cord? What will this swelling cause? In the Brain? In the Spinal Cord?

Ventricles: Cavities with CSF Cavities within the center of the brain filled with CSF This fluid is found in the space around the Meningies and the central canal of the spinal cord Fluid protects and cushions the CNS

CEREBROSPINAL FLUID FLOW Cerebrum Corpus Callosum Ventricles Hypothalamus: Homeostasis Thalamus Pituitary Gland: Master Gland Cerebellum Spinal Cord: sensory impulses up Motor impulses down

Cerebellum Inferior to the Occipital lobes Posterior to the Pons and Medulla Oblongata Co-ordinates complex skeletal muscle contractions and relaxation necessary for body movement and balance Connects the brain to the brain stem Cerebellum Thalamus Hypothalamus Pituitary gland

Medulla Oblongata Inferior part of brain stem Contains the vital reflexes Cardiovascular center: force and rate of the heart rate and changes in smooth muscle of the arteries to regulate Blood Pressure Respiratory centers: controls diaphragm Vomiting, hiccupping, swallowing, coughing, sneezing Medulla Oblongata

Pons Bulging brain stem region Bridge between the cerebellum and the cerebrum Works with the medulla oblongata to control breathing (respiration) Pons

Midbrain Form important connections between the cerebral cortex and the brainstem and spinal cord to control sensory processes such as vision and movement. Midbrain

Nerves: bundles of Neurons Electrical impulses (messages) travel back & forth between from the PNS to the CNS and then back to the PNS through bundles of neurons which are called nerves

Neurons: Five main parts 1 Dendrites: Extends out from the cell body picks up message from synaptic terminal of adjoining neuron 2 Cell Body: Directs all activity of the neuron

Neurons: parts 3 & 4 3 Axon: 4 Synaptic terminals or axon terminals: long single fiber that transmits electrical impulse from cell body to the synaptic terminals 4 Synaptic terminals or axon terminals: Release neurotransmitters that allows electrical message to travel to the next neuron’s Dendrites or gland or muscle cells

Neurons: part five 5 myelin sheath covers most neurons insulates the axon and helps nerve signals travel faster and farther.

Movement of neurotransmitters from synaptic terminal of one neuron: to the dendrites of another neuron Muscle cell : cardiac, skeletal, smooth gland For a synapse to occur you need to have a Pre-synaptic cell Post-synaptic cell Synapse

Neurotransmitters Acetylcholine – stimulates muscle contraction Monoamines - Norepinephrine & Dopamine sense of feeling good, low levels = depression Serotonin Sleepiness Depression Endorphins reduce pain by inhibit receptors

Interneurons Neurons in the CNS Brain Spinal cord White matter: Cell Body Neurons in the CNS Brain Spinal cord Gray Matter: Axons

Cross Section of the Spinal Cord Spinal nerve Central canal Gray matter White matter Meninges Spinal nerve Meningies

Reflex Arc: simples nerve circut Sensory: afferent stimuli DORAL ROOT Motor: efferent response VENRAL ROOT

Reflex Arc occurs in the Spinal cord or brain stem Reflex Arc requires: Sensory neuron to provide afferent input (stimuli) (Dorsal root) Interneuron to process (Gray matter) Motor neuron to send efferent output (response) (Ventral Root)

Reflex Arc in Knee

Reflex Arc

Spinal Cord Nerve messages are sent through the spinal cord to the brain to be processed Link between brain and rest of body (PNS) 31 pairs of spinal nerves Reflexes processed directly by spinal cord Reflex – quick, automatic, involuntary responses Result of reflex arcs – shortest nerve pathways